The output power of transmitters in a radio communications system is generally controlled in order to ensure that the power of transmitted signals is sufficiently high at the receiver end, while interference levels in the system are kept at acceptable levels. By employing power control, the interference levels in the system can be reduced. The quality experienced by the user, as well as system capacity, can thereby be improved. Furthermore, the power consumption of the transmitters in the system can be kept at lower levels.
When a radio base station in a radio communications system receives signals directly from a user equipment which the radio base station is serving, measurements on which the uplink power control can be based can be made by the radio base station on signals received directly from the user equipment. The uplink power control can be performed by controlling the transmission power of the user equipment.
However, in many radio communications systems, the communication between a user equipment and a radio base station may be performed via a repeater. The received uplink power at the radio base station then depends, inter alia, on the transmission power of the repeater. A way of achieving efficient uplink power control for such systems is desired, so that sufficient received signal powers and low interference levels in the system are ensured.